During Jehoram's reign, Edom rebelled against Judah's control and appointed their own king.
So Jehoram crossed over to Zair with all his chariots. Then at night he set out to attack the Edomites who had surrounded him and the chariot commanders, but his troops fled to their tents.
So Edom is still in rebellion against Judah's control today. Libnah also rebelled at that time.